3 DVD Players, 1 Controller
Brandspeak Communications (brandspeak.net) planned their display with 4 plasma monitors, each showing a different 4-minute video, all of them playing and repeating simultaneously. One solution would have been to use Pioneer DVD-7400 players with a synchronizer, but the budget was already set and the firm already owned 3 JVC DVD players. Enter BCD.

At BCD, we reviewed Brandspeak's requirements and arrived at the elegant solution of using one BCD VC-16b controller equipped with 4 infrared emitters. The JVC was not a machine we controlled so they sent one to us for a day so we could learn its characteristics. We were somewhat concerned that the little VC-16b would have enough power to drive 4 IR emitters, but that proved to be a non-issue. 

The controller and the 4 players were all on the same power strip. Each DVD had a single different video. Brandspeak programmed the DVD discs so that the PREVious command restarted the video. With telephone guidance from BCD, Brandspeak programmed the single controller with a command string similar to this:

 
 
>INI2 <a href="http://www.php.net/time"><span style="color: #000066">TIME</span></a> <span style="color: #cc66cc">300</span>; LOOP FOREVER; <a href="http://www.php.net/prev"><span style="color: #000066">PREV</span></a>; <a href="http://www.php.net/time"><span style="color: #000066">TIME</span></a> <span style="color: #cc66cc">2430</span>; LEND

• INI2 is the name of the command string that is issued when the VC-16b is first powered up (Cold Boot).
• Each unit of TIME is about a tenth of a second so when power was applied, the VC-16b waited 30 seconds for the discs to spin up.
• LOOP can have a number to designate how many times to repeat subsequent commands. FOREVER is a special parameter that goes... forever.
• PREV restarts all the videos
• TIME 2430 is about 4 minutes and 3 seconds... just enough time to let the videos finish.
• LEND means Loop END.

There are other ways to achieve absolute synchronization, but Brandspeak reported that with this installation, the timing differences between machines were unnoticed... about 1/4 second.